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. zsheets-sheet 1.- A. J. P. WHITAKER 8L P. G. TREHARNE. l

(N0 Model.)

INSULATOB. POR ELECTRICAL PURPOSES.

No. 566,045. Patented Aug. 18, 1896.

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(No Model.) 2 Sheets-Sheet 2.

A. J. P. WHITAKER & P. G. TRBHARNE.

' INSULATOE EOE ELECTRICAL PURPOSES.

No. 566,045. Patented Aug. 18, 1896.

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UNITED STATES PATENT OFFICE.

ALFRED JAMES PERTCN VVHITAKER AND FREDERICK GVILYM TREl-IARNE, OF LLANISHEN, ENGLAND.

INSULATOR FOR ELECTRICAL PURPOSES..

srEoIEroA'rIoN forming part of Letters rarest No. 566,045, dated August 18, 1896. Application nea sementa- 3,1895. sei-a1 No. 561,232. oto man.)

To aZ whom it may concern.-

Be it known that we, ALFRED JAMES PER- ToN XVHITAKER, chartered accountant, and FREDERICK GWILYM TREHARNE, analytical chemist, subjects of the Queen of Great Britain, residing at Llanishen, near Cardiff, England, have invented certain new and useful Improvements in and Relating to Insulators for Electrical Purposes, of which the followio ing is a specification, reference being had to the accompanying drawings.

Our invention relates to improved insulators for electrical purposes and chiefly for telegraph and telephone wires. The said insulators comprise a steel or other metal shell coated with a non-conducting enamel composed chiefly of silica and aluminium, and filled with a suitable insulating cement or composition.

2o We preferably carry our improved insulator by a spindle which may be coated with the non-conducting enamel aforesaid, and which is held in position in the shell and insulated therefrom by means of the before-mentioned cement or composition. Y

Referring to the accompanying drawings, Figure l is a side elevation of an insulator constructed according to our invention, and Fig. 2 is a vertical central section of the same.

3o Fig. 3 is an elevation, partly in section, of a modified form of insulator. Fig. 4 is a similar Aview of a further modification, the spindle yhaving been removed. Fig. 5 is a section on a smaller scale of a still further modified form 3 5 o f insulator furnished with two shells separated by insulating-cement.

A is the metal shell or body of the insulator.

B is the spindle.

C is the insulating cement or composition 4o which fills the shell A and receives the spindle B.

D is the non-conducting enamel coating, which is composed chiefly of silica and aluminium, together with, in the preferred form,

4 5 a more or less relatively small quantity of lime, barium, tin, and boraX.

The composition of the enamel may, for eX- ample, be as follows: silica, fty per cent. 5 aluminium, twenty per cent.; lime, live per 5o cent.; barium, live per cent.; oxid of tin, five per cent. boraX, fifteen per cent. Total, one hundred per cent.

The insulating-cement C is composed of sulfur, bitumen, sulfate of lime, sulfate of barium, silica, together with in some cases oXid of lead and resin, which substances may, for example, be advantageously combined in the following proportions: sulfur, twenty per cent.; bitumen, ten per cent.; sulfate of lime, twenty per cent.; sulfate of barium, 6c twenty per cent. 3 oxid of lead, live per cent.; resin, five per cent.; silica, twenty per cent. Total, one hundred per cent. The said insulating-cement is preferably placed in the shell A when in a plastic state, the spindle B being then held in position therein till the cement or composition sets and hardens. The spindle may be arranged to pass right through the insulator, as in the form shown in Figs. 3 and 4E, or it may only project into the 7o interior of the insulator, as shown in Fig. 2.

In either case the spindle is secured to and insulated from the shell A by means of the insulating-cement C.

The insulator shown in Fig. 5 is furnished 75 with a second metal shell E, inclosing the shell A and secured thereto by insulatingcement C at the upper or inner end. An annular space F unlled with cement is left between the body part of the two shells, as shown, 8o to diminish the risk of leakage when exposed to driving rain. The shell E is coated with enamel the same as the inner shell A.

In all cases the shells may be coated internally as well as externally with the enamel. 8 5

Our improved insulators are adapted for use in any climate.

IVhat we claim isl. The combination in an insulator, of a metallic shell, a non-conducting coating or 9o enamel thereon, a carrying-spindle, and a cement of insulating material within the said shell and serving to secure the same to the carrying-spindle.

2. An improvedinsnlator for electrical purposes comprising a metal shell coated with a non-conducting enamel, in combination with a spindle for carrying the insulator, and an insulating-cement for securing the said spindle within the shell, the said cement being roo therefrom by an insulating-cement at the inner end, an annular space being left between the body of the shells, substantially as described.

In testimony whereof We have hereunto set our hands this 22d day of July, 1895.

ALFRED JAMES PERTON WHITAKER.

FREDERICK GWILYM. TREHARNE. lVitnesses:

G. C. DOWNING, GEO. P. SURCHER.- 

